BOTOX (Onabotulinum toxin A)

What is this medication?

BOTOX (OnabotulinumtoxinA)
Neuromuscular Blocking Agent

BOTOX (OnabotulinumtoxinA) is officially indicated for cervical dystonia, glabellar lines, and spasticity depending on the product used.  Some formulations are also used off-label to treat acquired nystagmus, sialorrhea, and tardive dyskinesia.

ALERT: WARNING
Postmarketing reports indicate that the effects of all botulinum toxin products may spread from the area of injection to produce symptoms consistent with botulinum toxin effects. These may include asthenia, generalized muscle weakness, diplopia, blurred vision, ptosis, dysphagia, dysphonia, dysarthria, urinary incontinence, and breathing difficulties. These symptoms have been reported hours to weeks after injection. Swallowing and breathing difficulties can be life-threatening, and there have been reports of death. The risk of symptoms is probably greatest in children treated for spasticity, but symptoms can also occur in adults treated for spasticity and other conditions, particularly in those patients who have underlying conditions that would predispose them to these symptoms. In unapproved uses and in approved indications, cases of spread of effect have been reported at doses comparable to or lower than the maximum recommended total dose.

How does this medication work? 

Botulinum Toxin is a neurotoxin that prevent the calcium-dependent release of acetylcholine at the presynaptic membrane of the neuromuscular junction and consequently produces a state of denervation.  Muscle inactivation persists until new fibrils grow from the nerve and form junction plates on new areas of the sarcolemma.

Formulations: Two serotypes of Botulinum Toxin have been formulated for clinical use, including botulinum toxin type A (the most common serotype used for cosmetic applications) and botulinum toxin type B. In order to prevent confusion between products, in 2009, the US Food and Drug Administration (FDA) recommended the use of specific names, rather than serotypes, to refer to the available formulations of Botulinum Toxin.

How should I take this medication? 

The specific dosage and recommendations are dependent on the condition being treated.  Do not exceed a total dose of 360 units administered in a 3 month interval.  

Detrusor Overactivity associated with a Neurologic Condition
Recommended total dose 200 Units, as 1 mL (~6.7 Units) injections across 30 sites into the detrusor.

Chronic Migraine
Recommended total dose 155 Units, as 0.1 mL (5 Units) injections per each site divided across 7 head/neck muscles.

Upper Limb Spasticity
Select dose based on muscles affected, severity of muscle activity, prior response to treatment, and adverse event history; electromyographic guidance recommended.  

Cervical Dystonia
Base dosing on the patient’s head and neck position, localization of pain, muscle hypertrophy, patient response, and adverse event history; use lower initial dose in botulinum toxin naïve patients.

Axillary Hyperhidrosis
50 Units per axilla.

Blepharospasm
1.25 Units-2.5 Units into each of 3 sites per affected eye.

Strabismus
1.25 Units-2.5 Units initially in any one muscle.

Note: These dilutions are calculated for an injection volume of 0.1 mL. A decrease or increase in the BOTOX dose is also possible by administering a smaller or larger injection volume - from 0.05 mL (50% decrease in dose) to 0.15 mL (50% increase in dose).  Reconstituted BOTOX should be clear, colorless, and free of particulate matter. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration and whenever the solution and the container permit.

What should I watch for while using this medication? 

Do not use if cases of serious anaphylaxis and/or hypersensitivity to any component of Botulinum Toxin type A and B. Use with caution in patients with pre-existing cardiovascular disease. Systemic toxicity has been reported beyond the injection site.  Dysphagia and breaking difficulties have occurred and may be life threatening.

What if I miss a dose?

Only an experienced licensed trained medical professional should be administering Botulinum Toxin. Since Botulinum Toxin has a temporary effect and is given at widely spaced intervals, missing a dose is not likely to be harmful.

How should I store this medication?

Botox should be administered within twenty-four hours after reconstitution. During this time period, reconstituted Botox should be stored in a refrigerator (2° to 8° C). Reconstituted Botox should be clear, colorless and free of particulate matter. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration and whenever the solution and the container permit.

What are the possible side effects of using this medication?

Dysphagia, xerostomia, discomfort at the injection site, voice disorder, fatigue, headache, myasthenia, eye disease.

Note this is not a complete list of side effects for BOTOX (OnabotulinumtoxinA), only common ones.